171–180 of 209 posts
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Except that infinite precision requires infinite settling time. (Which I guess is the analogue computing version of arithmetic not being O(1) even though it is usually modelled that way.)
Infinite precision is just analog's version of an infinitely-long tape.
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It can? How?
as i understand it, with infinite precision; the real numbers within some range, say -15 volts to +15 volts, have a bijection to infinite strings of bits (some infinitesimally small fraction of which are all zeroes after a finite count). with things like the logistic map you can amplify arbitrarily small differences into totally different system trajectories; usually when we plot bifurcation diagrams from the logisti…
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This is a great technique to avoid common-mode failures.
Do you have data to back that claim up? I remember reading evidence to the contrary, namely that programmers working on the same problem -- even in different environments -- tend to produce roughly the same set of bugs. The conclusion of that study was that parallel development mainly accomplishes a false sense of security, and most of the additional reliability in those projects came from other sound engineering tec…
Leveson also wrote the report on Therac 25.
Earlier quoted context omitted.
Except that infinite precision requires infinite settling time. (Which I guess is the analogue computing version of arithmetic not being O(1) even though it is usually modelled that way.)
Infinite precision is just analog's version of an infinitely-long tape.
Earlier quoted context omitted.
For the Apollo Guidance Computer, changing the program meant manually re-weaving wires through or around tiny magnet rings. A good part of the cost of the computer was the time spent painstakingly weaving the wires to store the program.
Pardon me, but why would you have to re-weave wires around magnetic rings? The magnetic rings are for storing data; the whole point is that you can change the data without rewiring the memory. If you have to re-wire permanent storage (e.g. program storage), that's equivalent to creating a mask ROM, which is basically just two funny-shaped sheets of conductor. There's no need for magnetic rings.
https://en.wikipedia.org/wiki/Core_rope_memory input wires were energized, and they were coupled (or not) to the output wires depending on if they shared a magnetic ring (or not).
I'm curious - are there any ways of finding out the precise hardware that's used in these small-scale devices that are generally not considered to be computers (like smartphone chargers) without actually having to take them apart? Are there special datasheets, or perhaps some documents for government certification, or anything like it? I've always been fascinated with the barebones, low-spec hardware that runs mundan…
Today it's even more the case. You have fully programmable CPUs in your keyboard, trackpad, mouse, all usb devices, etc.
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Why would you expect there to be one? It’s all the same stuff and has been for decades.
I expect nation state actors to have immensely more access to computing power than the commercial sector, is that controversial?
What do you expect US government to do with lots of computing power? I wouldn’t expect military to need supercomputers. Maybe the NSA would have a lot for cracking something or surveillance. But the big tech companies have more.
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Except that infinite precision requires infinite settling time. (Which I guess is the analogue computing version of arithmetic not being O(1) even though it is usually modelled that way.)
Infinite precision is just analog's version of an infinitely-long tape.
Earlier quoted context omitted.
Could you explain "above arithmetic in the hierarchy" in a few words, TIA, never heard of this
Nope. The source page links to https://en.wikipedia.org/wiki/Arithmetical_hierarchy . I can't figure it out. An HN comment search, https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu... , finds a few more lay examples, with https://news.ycombinator.com/item?id=21210043 by dwohnitmok being the easiest for me to somewhat make sense of. I think the idea is, suppose you have an oracle which tells you if a Turnin…
https://risingentropy.com/the-arithmetic-hierarchy-and-compu...
I'm curious - are there any ways of finding out the precise hardware that's used in these small-scale devices that are generally not considered to be computers (like smartphone chargers) without actually having to take them apart? Are there special datasheets, or perhaps some documents for government certification, or anything like it? I've always been fascinated with the barebones, low-spec hardware that runs mundan…